JP2004188687A - Inkjet head and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet head which prevents clogging of a nozzle caused by the protrusion of an adhesive for forming an adhesive layer. <P>SOLUTION: This inkjet head comprises: a nozzle plate 16 wherein the nozzles 15 for ejecting ink are formed; a head body 11 which is provided with a pressure chamber formed in the state of communicating with the nozzles 15 via an ink passage 17, so as to store the ink, and an actuator for applying pressure to the ink in the pressure chamber so as to eject the ink from the nozzles 15; and the adhesive layer 12 which is provided between the nozzle plate 16 and the head body 11 so as to bond the nozzle plate 16 and the head body 11 together. A distance p between an adhesive layer-side end of the ink passage 17 and an adhesive layer-side end of the nozzle 15, which is located inside the above end, and a width t of the adhesive layer 12 have the relationship of 0≤p≤2t; and the angle θ1 of the adhesive layer-side axial cross section of the nozzle 15 is set to be in the range of 45°≤θ1≤110°. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inkjet head and an inkjet recording apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an inkjet head in which a nozzle plate in which a plurality of nozzles are formed is joined to a head body is known. In this type of inkjet head, the head body includes a plurality of pressure chambers for storing ink, an ink flow path connected to each pressure chamber, and an actuator that applies pressure to the ink in the pressure chamber and ejects ink from a nozzle. Is provided.
[0003]
The nozzle plate is joined to the head body such that each nozzle is connected to each ink flow path. Then, when the actuator applies pressure to the ink in the pressure chamber, a part of the ink in the pressure chamber flows through the ink flow path and is ejected from the nozzle as an ink droplet.
[0004]
By the way, when joining the nozzle plate and the head main body, an adhesive is often used. However, since the diameter of the nozzle and the ink flow path is extremely small, there is a problem in bonding.
[0005]
That is, the adhesive may protrude into the ink flow path and the nozzles, which may cause ink ejection failure. In other words, when the adhesive overflows, not only does the flow resistance of the ink increase, and the desired ink ejection performance cannot be obtained, but also the adhesive that has overflowed flows into the nozzle during thermosetting, and the nozzle is clogged. Cause it.
[0006]
Therefore, various techniques have been proposed to prevent the above-mentioned adverse effects. For example, Japanese Patent Laid-Open Publication No. Hei 5-330067 proposes providing a head escape groove for the adhesive in order to prevent the adhesive from protruding into the ink flow path. Japanese Patent Application Laid-Open No. 2001-63052 proposes that a head body is formed by laminating a plurality of flow path plates, and through holes are provided in the flow path plates to allow air to escape in a laminating direction. I have.
[0007]
[Patent Document 1]
JP-A-5-330067 (FIG. 1)
[Patent Document 2]
JP 2001-63052 A (FIG. 1)
[0008]
[Problems to be solved by the invention]
However, in the ink jet head disclosed in JP-A-5-330067 and JP-A-2001-63052, it is necessary to provide an escape groove or a through hole in the head body, so that the structure of the head body becomes complicated, This has led to a decrease in yield and an increase in manufacturing cost.
[0009]
When a thermosetting adhesive or the like is used as the adhesive, by-products such as gas and moisture may be generated in the process of drying and curing. However, in the above-described ink jet head, the adhesive is applied to the head body or the nozzle plate in a solid manner, and no consideration is given to by-products.
[0010]
Accordingly, it is an object of the present invention to provide an ink jet head and an ink jet recording apparatus which can prevent nozzle clogging caused by protrusion of an adhesive forming an adhesive layer.
[0011]
[Means for Solving the Problems]
In order to solve this problem, an inkjet head according to the present invention includes a nozzle plate in which a plurality of nozzles from which ink is ejected are formed, and a pressure formed in communication with the nozzle through an ink flow path to store the ink. A head body provided with an actuator that applies pressure to the ink in the chamber and the ink in the pressure chamber to eject ink from the nozzles, and is provided between the nozzle plate and the head body, and adheres the nozzle plate and the head body. When the distance between the adhesive layer side end of the ink flow path and the adhesive layer side end of the nozzle located inside the end is p, and the thickness of the adhesive layer is t. , The distance p and the thickness t have a relationship of 0 ≦ p ≦ 2t, and the angle θ1 of the axial section on the adhesive layer side of the nozzle is 45 degrees ≦ θ1 ≦ 110 degrees.
[0012]
According to this, it becomes possible to prevent the nozzle from being clogged due to the protrusion of the adhesive forming the adhesive layer.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the first aspect of the present invention, there is provided a nozzle plate in which a plurality of nozzles from which ink is ejected are formed, a pressure chamber formed in communication with the nozzle via an ink flow path, and storing the ink, and A head body provided with an actuator that applies pressure to the ink in the pressure chamber and ejects ink from the nozzles, and an adhesive layer that is provided between the nozzle plate and the head body and bonds the nozzle plate and the head body. When the distance between the adhesive layer side end of the ink flow path and the adhesive layer side end of the nozzle located on the inner side of the end is p, and the thickness of the adhesive layer is t, the distance p And the thickness t have a relationship of 0 ≦ p ≦ 2t, and the angle θ1 of the axial section on the adhesive layer side of the nozzle is 45 ° ≦ θ1 ≦ 110 °. Start to protrude This has the effect that it is possible to prevent nozzle clogging due to this.
[0014]
The invention according to claim 2 of the present invention is the inkjet head according to claim 1, wherein the thickness t of the adhesive layer is t = 1 to 5 μm, and the adhesive forming the adhesive layer protrudes. This has the effect that it is possible to prevent clogging of the nozzle caused by this.
[0015]
According to a third aspect of the present invention, in the inkjet head according to the first or second aspect, an angle θ2 of an axial section of the ink flow path on the adhesive layer side is 45 degrees ≦ θ2 ≦ 110 degrees. There is an effect that it is possible to prevent clogging of the nozzle due to protrusion of the adhesive forming the adhesive layer.
[0016]
The invention according to claim 4 of the present invention is the inkjet head according to any one of claims 1 to 3, wherein the adhesive layer is formed by applying an adhesive by a screen printing method. This has the effect that it is possible to prevent nozzle clogging due to the protrusion of the adhesive forming the adhesive layer.
[0017]
According to a fifth aspect of the present invention, there is provided an ink jet recording apparatus provided with the ink jet head according to any one of the first to fourth aspects. This has the effect that printing can be performed.
[0018]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In these drawings, the same members are denoted by the same reference numerals, and redundant description is omitted.
[0019]
FIG. 1 is a perspective view showing an overall schematic configuration of a recording apparatus provided with the inkjet head of the present invention. FIG. 2 is a cross-sectional view showing an inkjet head according to an embodiment of the present invention mounted on the recording apparatus of FIG. FIG. 3 is a cross-sectional view showing an axial cross-sectional shape which is an example of a nozzle in the inkjet head of the present invention. FIG. 4 is a cross-sectional view showing an axial cross-sectional shape which is another example of the nozzle in the ink jet head of the present invention. Is a graph showing the relationship between the angle of the axial section on the adhesive layer side of the nozzle in the inkjet head of the present invention and the clogging rate of the nozzle, and FIG. 6 is an axial direction which is an example of the ink flow path in the inkjet head of the present invention. 7 is a cross-sectional view showing another example of the ink flow path in the ink jet head of the present invention in the axial direction.
[0020]
An ink jet recording apparatus (recording apparatus) 40 shown in FIG. 1 includes an ink jet head (ink ejection head) 41 for performing recording by using a piezoelectric effect of a ferroelectric element constituting an actuator, and an ink tank (not shown). ), The ink droplets ejected from the inkjet head 41 and landed on a recording medium 42 such as paper to record on the recording medium 42. The inkjet head 41 is mounted on a carriage 44 provided on a carriage shaft 43 arranged in the main scanning direction X, and reciprocates in the main scanning direction X as the carriage 44 reciprocates along the carriage shaft 43. Move. Further, the ink jet recording apparatus 40 includes a plurality of rollers (moving means) 45 for moving the recording medium 42 in the sub scanning direction Y substantially perpendicular to the width direction of the ink jet head 41 (that is, the main scanning direction X). .
[0021]
As shown in FIG. 2, the inkjet head 41 has a nozzle plate 16 in which a plurality of nozzles 15 are formed, and a head body 11 to which the nozzle plate 16 is joined.
[0022]
Here, the head main body 11 includes a flow path plate 19, and a pressure chamber member 13 formed by stacking partition members 24 and actuators 25 that partition the pressure chamber 23.
[0023]
The flow path plate 19 includes an ink flow path 17 that connects the pressure chamber 23 and the nozzle 15, a common ink chamber 18 that introduces ink into the pressure chamber 23, and a common ink chamber 18 and the pressure chamber 23. An ink supply path 20 communicating with the ink supply path is provided. The channel plate 19 is formed by laminating a plurality of thin plates. Here, the channel plate 19 is formed of five thin plates. As the thin plate, for example, stainless steel or the like can be suitably used.
[0024]
The partition member 24 of the pressure chamber member 13 is formed of photosensitive glass. However, the type of the partition member 24 is not limited to photosensitive glass. A pressure chamber 23 is formed in the partition member 24 so as to extend over the ink supply path 20 of the flow path plate 19 and the ink flow path 17. The pressure chambers 23 are formed in a long groove shape so as to extend in the main scanning direction X, and are arranged at predetermined intervals in the sub-scanning direction Y.
[0025]
The actuator 25 is provided on the upper surface of the partition member 24 (the surface opposite to the side where the nozzle plate 16 is provided) so as to cover the pressure chamber 23 of the partition member 24. The actuator 25 is a so-called piezo-type actuator using the piezoelectric effect of a piezoelectric element, and is particularly a flexural vibration type actuator. The actuator 25 expands and contracts the volume of the pressure chamber 23 by bending deformation of the actuator 25, and discharges ink droplets from the nozzle 15 by the pressure change in the pressure chamber 23 due to the expansion and contraction, and the common ink chamber 18. To fill the pressure chamber 23 with ink.
[0026]
Although not shown, the actuator 25 is configured by sequentially laminating a vibration plate that covers the pressure chamber 23, a thin-film piezoelectric element that vibrates the vibration plate, and individual electrodes. The diaphragm is made of a chrome plate having a thickness of 2 μm, and also has a function as a common electrode for applying a voltage to the piezoelectric element together with the individual electrodes. The piezoelectric element is provided corresponding to the pressure chamber 23, and PZT (lead zirconate titanate) having a thickness of 0.5 μm to 5 μm can be suitably used. In the present embodiment, the thickness of the piezoelectric element is set to 3 μm. The individual electrodes are made of a platinum plate having a thickness of 0.1 μm, and the entire thickness of the actuator 25 is about 5 μm.
[0027]
The overall thickness of the head body 11 is set to, for example, 480 μm. The nozzle plate 16 is formed of a polyimide plate having a thickness of 20 μm.
[0028]
When the actuator 25 applies pressure to the ink in the pressure chamber 23, a part of the ink in the pressure chamber 23 flows through the ink flow path 17 and is ejected from the nozzle 15 as an ink droplet.
[0029]
As shown, the adhesive layer 12 is interposed between the flow path plate 19 and the nozzle plate 16. That is, the nozzle plate 16 and the head body 11 are joined to each other by the adhesive forming the adhesive layer 12. The type of the adhesive is not particularly limited, and for example, an epoxy-based, silicone-based, or acrylic-based adhesive can be suitably used. However, epoxy adhesives are excellent in ink resistance, rigidity, thixotropy, etc., and therefore epoxy adhesives are particularly preferred from the viewpoint of improving reliability and adhesive strength.
[0030]
The adhesive is desirably applied to the nozzle plate 16 or the head main body 11 by a screen printing method.
[0031]
In the screen printing, an adhesive is applied to a bonding surface of the nozzle plate 16 in a predetermined pattern. Here, a method of applying a resin adhesive to the nozzle plate 16 as an adhesive will be described. However, it may be applied to the head body 11.
[0032]
When applying the adhesive, first, a mesh (not shown) formed in a shape corresponding to the arrangement pattern of the adhesive is made to face the bonding surface of the nozzle plate. Next, the adhesive is placed on the mesh, and the adhesive is pressed against the nozzle plate 16 from above the mesh by a squeegee (not shown). As a result, the adhesive is pushed into the small holes of the mesh, and the adhesive is arranged on the nozzle plate 16 in a predetermined pattern.
[0033]
After the adhesive is applied onto the nozzle plate as described above, the nozzle plate 16 and the head main body 11 are aligned, and the nozzle plate 16 and the head main body 11 are pressed against each other and adhered. Then, after the nozzle plate 16 and the head main body 11 are bonded to each other, heat curing is performed for a predetermined time.
[0034]
According to such a screen printing method, the adhesive can be arranged in a desired pattern with high accuracy.
[0035]
Here, in the present embodiment, an adhesive having a thickness of 1 μm to 20 μm is applied, and the adhesive is cured by pressure to form an adhesive layer 12 of 1 μm to 10 μm (preferably about 1 to 5 μm). did.
[0036]
Here, the inventor considered the axial cross-sectional shape of the nozzle 15 in the inkjet head. That is, the angle θ1 of the axial section on the adhesive layer side of the nozzle 15 was gradually changed from an obtuse angle to an acute angle as shown in FIG. 3, and data on the angle θ1 and the clogging rate of the nozzle 12 were collected.
[0037]
In this case, the distance p between the end of the ink flow path 17 on the adhesive layer side and the end of the nozzle 15 located on the inner side of this end and the thickness t of the adhesive layer are 0. ≤p≤2t.
[0038]
The diameter of the opening of the nozzle 15 was 20 to 50 μm, and the diameter of the adhesive layer side was 35 μm. Further, the diameter of the ink flow path 17 is 40 μm, the above-described distance p is 2.5 μm, and the thickness t (after the adhesive is cured) is 3 μm. The present invention is, of course, not limited to these numerical values.
[0039]
The data obtained is shown in FIG.
[0040]
FIG. 5 shows that when the angle θ1 is 110 ° or more, the clogging rate is rapidly deteriorated, and thus it is not suitable for use as a nozzle of an inkjet printer.
[0041]
Further, when the angle θ1 is 110 degrees or less, a phenomenon in which the clogging rate of the nozzle deteriorates remarkably does not occur. However, if the angle θ1 is less than 45 degrees, the angle is too shallow and the opening of the nozzle 15 becomes very large, making it difficult to realize a high-density nozzle 12.
[0042]
Therefore, the optimal angle θ1 of the axial section on the adhesive layer side of the nozzle 12 is 45 ° ≦ θ1 ≦ 110 °.
[0043]
The inventor also considered the angle θ2 of the axial section on the adhesive layer side of the ink flow path 17 (FIGS. 6 and 7). As a result, similarly to the angle θ1, the clogging rate rapidly deteriorated at 110 ° or more. If the angle θ2 is less than 45 degrees, the angle is too shallow and close to a step, and ink flow near the nozzle 15 becomes unstable.
[0044]
Therefore, the angle θ2 of the axial section on the adhesive layer side of the ink flow path 17 also becomes optimal when 45 ° ≦ θ2 ≦ 110 °.
[0045]
In the present invention, the angle θ1 may be 45 to 110 degrees, and the angle θ2 may not satisfy this condition.
[0046]
Thus, in the ink jet head of the present embodiment, the distance p between the adhesive layer side end of the ink flow path 17 and the adhesive layer side end of the nozzle 15 and the thickness t of the adhesive layer 12 are 0 ≦ p. ≦ 2t, and the angle θ1 of the axial section on the adhesive layer side of the nozzle 15 is set to 45 degrees ≦ θ1 ≦ 110 degrees, so that the angle of the axial section on the adhesive layer side of the ink flow path 17 is further increased. Since θ2 is set to 45 degrees ≦ θ2 ≦ 110 degrees, it is possible to prevent the nozzle 15 from being clogged due to the protrusion of the adhesive forming the adhesive layer 12.
[0047]
Therefore, in an ink jet recording apparatus including such an ink jet head, it is possible to perform high-quality printing with good ink ejection performance without clogging.
[0048]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain an effective effect that it is possible to prevent nozzle clogging due to protrusion of an adhesive forming an adhesive layer.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an overall schematic configuration of a recording apparatus provided with an ink jet head of the present invention. FIG. 2 is a cross-sectional view showing an ink jet head according to an embodiment of the present invention mounted on the recording apparatus of FIG. FIG. 3 is a cross-sectional view illustrating an axial cross-sectional shape as an example of a nozzle in the inkjet head of the present invention. FIG. 4 is a cross-sectional view illustrating an axial cross-sectional shape of another example of a nozzle in the inkjet head of the present invention. 5 is a graph showing the relationship between the angle of the axial cross section on the adhesive layer side of the nozzle in the ink jet head of the present invention and the clogging rate of the nozzle. FIG. 6 is an example of the ink flow path in the ink jet head of the present invention. FIG. 7 is a cross-sectional view showing another example of the ink flow path in the ink jet head of the present invention. Description of]
DESCRIPTION OF SYMBOLS 11 Head main body 12 Adhesive layer 15 Nozzle 16 Nozzle plate 23 Pressure chamber 25 Actuator 40 Ink jet recording device 41 Ink jet head

Claims (5)

A nozzle plate on which a plurality of nozzles from which ink is ejected are formed,
A pressure chamber formed in communication with the nozzle through an ink flow path and storing the ink, and a head body provided with an actuator that applies pressure to the ink in the pressure chamber and ejects the ink from the nozzle;
An adhesive layer is provided between the nozzle plate and the head main body, and adheres the nozzle plate and the head main body,
When the distance between the adhesive layer side end of the ink flow path and the adhesive layer side end of the nozzle positioned inside the end is p, and the thickness of the adhesive layer is t, the distance is p and the thickness t have a relationship of 0 ≦ p ≦ 2t,
An inkjet head, wherein an angle θ1 of an axial section of the nozzle on the adhesive layer side is 45 ° ≦ θ1 ≦ 110 °. 2. The ink jet head according to claim 1, wherein the thickness t of the adhesive layer is t = 1 to 5 [mu] m. The inkjet head according to claim 1, wherein an angle θ2 of an axial cross section of the ink flow path on the adhesive layer side satisfies 45 degrees ≦ θ2 ≦ 110 degrees. The inkjet head according to claim 1, wherein the adhesive layer is formed by applying an adhesive by a screen printing method. An ink jet recording apparatus comprising the ink jet head according to claim 1.

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